Tube bending apparatus

ABSTRACT

Tube bending apparatus includes mechanism for advancing a tube to selected longitudinal positions between a ram die, a stationary wing die and a rotatable wing die; rotating the tube to selected orientations; and bending the tube to selected depths of bend by advancing the ram die towards the wing dies and against the tube to stretch and thereby bend the tube therearound. Hydraulic mechanism is included to balance the clamping pressures applied by the dies during the bending operation. The set of dies is designed to be removable. Thereby, the apparatus may be set up to handle different diameter tubes and to make bends along different radii by changing dies. One embodiment of apparatus is arranged to feed tubing to either of two die sets. One die set is designed for bending right-handed bent tubes while the other is designed for making left-handed bent tubes.

United States Patent [191 Lance [451 May 7,1974

[ TUBE BENDING APPARATUS I [76] Inventor: Bruce J. Lance, 1460 Chase Dr.,

Corona, Calif. 91720 [22] Filed: July 3, 1972 21 Appl. No.: 268,775

Related US. Application Data [63] Continuation-in-part of Ser. No. 60,328, Aug. 3, 1970, which is a continuation-in-part of Ser. No. 740,809, May 31, 1968.

[52] US. Cl 72/7, 72/21, 72/DIG. 22 [51] Int. Cl B21d 7/12 [58] Field of Search 72/7, 19,20, 21, 22, 32, 72/DlG. 22, 149,217

[56] References Clted UNlTED STATES PATENTS 3,557,585 1/l97l lnda 72/7 3,388,574 6/1968 lgnoffo.... 72/22 3,209,570 10/1965 Hills 72/2l 3,339,385 9/l967 Lance 3,387,473 6/l968 Noordhoekm, 3,l8l,323 5/l965 Bos 3,426,562 2/1969 lnda 72/7 3,429,l57 2/1969 Huth 72/32 Primary ExaminerRichard J. Herbst Assistant ExaminerM. J. Keenan Attorney, Agent, or Firm-Huebner & Worrel [57] ABSTRACT Tube bending apparatus includes mechanism for advancing a tube to selected longitudinal positions be-' tween a ram die, a stationary wing die and a rotatable wing die; rotating the tube to selected orientations; and bending the tube to selected depths of bend by advancing the ram die towards the wing dies and against the tube to stretch and thereby bend the tube therearound. Hydraulic mechanism is included to balance the clamping pressures applied by the dies during the bending operation. The set of dies is designed to be removable. Thereby, the apparatus may be set up to handle different diameter tubes, and to make bends along different radii by changing dies. One embodiment of apparatus is arranged to feed tubing to either of two die sets. One die set is designed for bending right-handed bent tubes while the other is designed for making left-handed bent tubes.

24 Claims, 32 Drawing Figures Fw. v2 52x51 m/vce um mNP W 5; Q m Mf W r IYBY FIG. 11.

PA'TENTEBMAY 7 m4 WNW saw on HF 11 wwm slaoeLess PATENTEDIM 7 L974 od p PATENTEDHAY 7 I974 3808.856

, sum 07 nr 11 I96- .16. 9 2 331 PATENTEUHAY 1 197:.

smin user 11 TUBE BENDING APPARATUS CROSS-REFERENCE TO RELATED APPLICATION This is a continuation in part of nowabandoned application, Ser. No. 60,328, filed 3 Aug. 1970, which, in turn is a continuation in part of now abandoned application, Ser. No. 740,809 filed May 31, 1968.

BACKGROUND OF THE INVENTION The present invention relates to bending apparatus and more particularly to improved apparatus for bending tubing, tubular stock and the like. Such improved bending apparatus is particularly suitable for forming automobile exhaust pipes from straight tubular stock.

is bent while the term radius of bend refers to the radius of the are along which the bend is made.

Further, each of the several bends made in the tubing have designed angular orientations with respect to each other about the longitudinal axis of the tube. For example, the plane defined by the first bend made in a tube extends radially outward from the longitudinal axis of the tube at what may be referred to as a reference position. The tube may then be rotated a selected number of degrees, for example 90 degrees, in a selected direction from this reference position so that the next bend made in the tube extends radially outward from the tubes longitudinal axis at an orientation 90degrees different from the first bend. Thus, the orientation of bend of the second bend with respect to the first is said to be 90 in the selected direction the tube wa'srotated.

It is also a common practice in the manufacture of many automobiles to incorporate a pair of exhaust pipes made up of so-called right and left-handed pipes. The right-handed exhaust pipe generally is a mirror image of the left-handed one.

As a consequence of the above, a need is presented for a versatile tube bending apparatus capable of being programmed to automatically and repeatedly form lengths of tubular stock into exhaust pipes having a plurality of longitudinally spaced apart bends in which each bend is made with a selected angle of bend at a predetermined orientation. Further, a need exists for a tube bending apparatus capable of being readily and easily set up to handle tubular stock of different radii and to form both right and left-handed pipes of exhaust pipe pairs.

Heretofore, various tube bending devices have been developed, both of the manual and automated types. Generally, however, these prior art benders have been deficient in that they have lacked one or more of the aforementioned desired capabilities. Further, prior art benders capable of being set up to handle tubular stock of different diameters or to make bends along different radii have generally required extensive setup time and complicated adjustment to do so.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide an improved apparatus for bending tubing, tubular stock and the like which is capable of repeatedly forming lengths of tubular stock into exhaust pipes of predetermined shapes which have a plurality of bends longitudinally spaced apart at preselected distances, the bends having selected angles of bend at predetermined orientations with respect to each other and the longitudinal axis of the tube.

Further it is an object of the present invention to provide an improved bending apparatus as set forth capable of being readily and easily set up to handle and bend tubular stock of different diameters, to make bends along different radii and/or to form both right and left-handed pipes of exhaust pipe pairs.

Additionally, it is an object of the present invention to provide an improved apparatus for forming bends of controlled characteristics in tubing, tubular stock and the like which is capable of making bends in a rapid, precise and repeatable manner. I

In accomplishing these and other objects, there is provided in accordance with the present invention tube bending apparatus capable of being set up and/or programmed to repeatably bend lengths of tubular stock into desired shapes, for example, to make automobile exhaust pipes. The tube bending apparatus includes a ram die, a stationary wing die and a rotatable wing die and mechanism for axially advancing a length of tubing to selected longitudinal positions between the dies. Mechanism is included for rotating the tube to selected orientations and bending the tube to selected depths of bend by advancing the ram die towards the wing dies and against the tube to stretch and thereby bend the tube therearound. Hydraulic mechanism including a pair of hydraulic cylinders interconnected through a .manifold is included to balance the clamping pressures applied by the dies during the bendingoperation. One hydraulic cylinder is physically connected to measure the clamping pressure between the ram die and the stationary wing die while the other hydraulic cylinder is physically connected to measure the clamping pressure between the ram die and the rotatable wing die. The dies are preferably designed to be removable and shims or spacers are included on the base of the dies to enable the apparatus to be set up to handle different diameter tubes and make bends along different radii simply by changing die sets. One embodiment of apparatus includes two, preferably laterally spaced apart, die set arrangements and a pivot arrangement for pivoting the tube feed mechanism of the apparatus to selectively feed either of the die sets. One die set arrangement is designed for making right-handed exhaust pipes and the other is designed for forming left-handed exhaust pipes.

Additional objects of the present invention reside in the specific construction of the exemplary embodiments of tube bending apparatus hereinafter particularly described in the specification and shown in the several drawings.

FIG. 1 is an elevation view of one side of one embodiment of tube bending apparatus according to the present invention showing the arrangement of the various elements which cooperate in bending a length of tubing into a desired configuration.

FIG. 2 is an elevation view of the other side of the tube bending means appearing at the upper left of FIG. 1.

FIG. 3 is a fragmentary view of the apparatus taken along line 3-3 of FIG. 1 showing the tube holding means.

FIG. 4 is a fragmentary plan view taken along line 4-4 of FIG. 1 partly broken away to show internal construction and showing a length of tubing held in the tube holding means. I

FIG. 5 is an elevation view of the same side of the tube bending means appearing in FIG. 1 showing the tube bending means at its starting attitude and partly broken away to show internal construction.

FIG. 6 is an end view of the tube bending means showing it as it would appear looking at the left end of the apparatus as shown in FIG. 1.

FIG. 7 is a fragmentary plan view of the tube bending means taken along line 7-7 of FIG. 5.

FIG. 8 is a fragmentary side elevation of the tube bending means taken along line 8-8 of FIG. 7.

FIG. 9 is a view taken along the line 9-9 of FIG. 5.

FIG. 10 is a fragmentary end view of the tube bending means taken along line 10-10 of FIG. 5 partly broken away to show internal construction.

FIG. 11 is a side elevation of the tube bending means of FIG. 1 shown at a position immediately prior to starting to form a bend in the tubing, partly broken away to show the orientation of the internal elements at this point in the operational cycle.

FIG. 12 is a side elevation of the tube bending means of FIG. 1 illustrating its position during the forming of a bend in the tubing and partly broken away to show the orientation of the internal elements at this position in the operational cycle.

FIG. 13 is a side elevation view of another embodiment of tube bending apparatus according to the present invention.

FIG. 14 is a plan view of the apparatus of FIG. 13.

FIG. 15 is a view taken along the line 15-15 of FIG. 14.

FIG. 16 is a view taken along the line 16-16 of FIG. 13.

FIG. 17 is a view taken along the line 17-17 of FIG.

FIG. 18 is a view taken along the line 18-18 of FIG.

FIG. 19 is a view taken along the line 19-19 of FIG. 17.

FIG. 20 is a side elevation view of the bending dies of the apparatus of FIG. 13 taken along the line 20-20 of FIG. 15 illustrating a tube clamped between the tance to the movement of the bending dies relative to each other. 1

FIG. 23 is a view taken as in FIG. 22 illustrating the positioning of the hydraulic resistance cylinders during the operation of bending a tube as shown in FIG. 21.

FIG. 24 is a diagram of a suitable hydraulic circuit arrangement for controlling the operation of the hydraulic ram cylinder and hydraulic resistance cylinders of the apparatus of FIG. 13.

FIGS. 25 and 26 are side elevation views of the depth of bend gauge mechanism of the apparatus of FIG. 13 illustrating the method in which a tape is prepared for use in programming the operation of the depth of bend gauge mechanism.

FIG. 27 is a view taken along line 27-27 of FIG. 26.

FIG. 28 is a sideelevation view of the depth of bend gauge mechanism of the apparatus of FIG. 13 in the process of making a bend.

FIG. 29 is a side elevation view of the depth of bend gauge mechanism of the apparatus of FIG. 13 upon completion of making a bend.

FIG. 30 is a cutaway view of the area enclosed in the dashed line 30 of FIG. 29.

FIG. 31 is a cutaway view of the area enclosed in the dashed line 31 of FIG. 29.

FIG. 32 is a diagram of a suitable electrical circuit arrangement for programming the operation of the tube bending apparatus of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIRST EMBODIMENT Referring now to the drawings, FIG. 1 is a side view of one embodiment of tube bending apparatus illustrating the general arrangement of the various elements which cooperate in bending a length of tubing or similar member into a desired configuration. Numeral 10 designates a supporting means in the form of a heavy base cabinet for supporting a tube bending mechanism or means 12, a tube supporting frame 14, and a stationary jaw or vise means 15. Tube supporting frame 14 has a plurality of spaced U-shaped supports 17 attached to supporting means 10 by mounting brackets 18.,Horizontally disposed guide means in the form of rails 20 extend longitudinally of supporting frame 14 and are affixed to the upper ends of U-shaped supports 17.

A tube holding means 22 for supporting one end of a length of tubing 27 is carried by supporting frame 14. As can be seen in FIGS. 3 and 4, tube holding means 22 has a central chuck or gripping means 24 rotatably mounted in a housing 26. An indexing means in the form of a circular protractor 28 is provided on one face of housing 26 to allow tubing 27, when held by gripping means 24, to be rotated through a preselected angle. A set screw 30 on drum 26 cooperates with gripping means 24 so that the tubing may be locked in the desired rotational orientation. Roller means in the form of rollers 32 are mounted on housing 26 for rotational engagement with rails 20. As shown in FIG. 1, a conveyor means 34 is supported by supporting frame 14 and is operatively associated with holding means 22. Conveyor means 34 may be manually or motor driven by driving means 35, and serves to move tube holding means 22 to any desired position along the length of supporting frame 14. As can be seen by again referring the form of a mounting column 42 comprising a pair of spaced side members 43, a front plate 44 disposed in a plane normal to side members 43 and affixed thereto as by welding, and a back plate 46 also rigidly affixed as by welding to side members 43 and disposed in a spaced parallel relationship with front plate 44. A yoke member48 is disposed transversely of side members 43 near their upper extremities and has a right and left arm projecting outwardly therefrom.

As can be seen by referring to FIGS. 7, 8 and 9, at the lower right side of bending means 12 a short splined shaft 50 extends through and is supported near its first or forward end by bearing 52 carried by front plate 44. The second end of shaft 50 is supported by bearing 54 carried by rear plate 46. A nut 56 is threadably affixed to the second end of shaft 50 and serves to hold the shaft in the correct operative position relative to bearings 52 and 54. Also affixed to the second end of shaft 50 is a valve actuator arm 57, the purpose of which will be discussed hereinafter.

A heavy plate 58 of stationary jaw means is rigidly affixed, as by welding, to the forward end of shaft 50 and a jaw, vise element or wing die 59 is removably supported by support plate 58. A sleeve 60 is disposed between front plate 44 and rear plate 46, and is adapted to operatively mate with the splines of splined shaft 50.

Referring now to FIGS. 8 and 10, an arrangement, similar to that just described, can be seen at the lower left side of bending means 12. As seen in these views, a short splined shaft62 extends through and is rotatably supported at its first or forward end by bearing 64 carried by front plate 44. The second end of shaft 62 is rotatably supported by bearing'66 carried by rear plate 46. Operatively associated with and located at the second end of shaft 62 is a depth of bend control means 68 for controlling the depth or degree of bend to be made in the tubing. The operation of control means 68 will presently be described in greater detail. Affixed at the forward end of shaft 62 and adapted to rotate with it is a first tube forming means 70 comprising a heavy support plate 71 and a first forming element or wing die 72 removably supported by plate 71. A sleeve 73 is disposed between plates 44 and 46 and is adapted to appropriately mate with the splines of splined shaft 62 so as to rotate with it.

Referring again to FIG. 5, ears 74 can be seen to project outwardly from sleeves 60 and 73. Pins 76 extend through the outer extremities of ears 74 and pivotally engage the bifurcated ends 77 of piston rods 78 and 79. Piston rod 78 carries a piston (not shown) which is movable within compression cylinder 80 and piston rod 79 carries a piston (not shown) which is movable within compression cylinder 81. Compression cylinders 80 and 81 have bifurcated upper ends 84 which are affixed by pins 86 to the right and left extremities, respectively, of the yoke member 48 of mounting column 42. The important function of the pivot resisting means 6 thus just described and provided by the compression pistons 80 and 81 will be presently discussed.

Mounted on mounting column 42 between the upper ends of side members 43 is a second forming means 88. Second forming means 88 comprises a hydraulic ram cylinder 90 housing a ram 92 which has a second forming element or ram die 94 removably affixed to its lower extremity. As can be seen in FIG. 6, the ram die 94 is in slidable engagement with guide rods 96 which are affixed to mounting column 42. Guide rods 96 are adapted and arranged to insure proper mating of the ram die 94 with the rotatably mounted wing die 72 of forming means 70 as ram 92 moves downwardly.

As is well known to those skilled in the art of hydraulics, operating or moving means in the form of a hydraulic system made up of standard components may be successfully used to operate the embodiment ofapparatus of the type here described and cause the desired relative movement among the forming means and their dies which cooperate in clamping and bending the tubing. Such a system generally includes a motor, a pump, a reservoir containing suitable hydraulic fluid, conduits for carrying fluid to and from the reservoir to the cylinders, and control valves which may be manually or automatically operated to control fluid flow within the system. In this embodiment of the apparatus of my invention, such a system is used with the components suitably arranged and interconnected with compression cylinders 80 and 81 and ram cylinder 90 of bending means 12.

When a control valve is moved to a start position by I an operator, fluid under pressure is delivered by conduit 98 to hydraulic ram cylinder 90. This causes ram 92 to move downwardly to the position shown in FIG. 11. As illustrated by this view, a length of tubing 27 positioned for bending is supported by the wing die 59 of stationary jaw means 15 and the wing die 72 of first forming means 70. As can be seen in FIGS. 6 and 7, the wingdies 59 and 72 have grooved central portions generally cylindrical in shape which are in alignment with each other and also are in alignment with a similarly grooved portion of the ram die 94. Die elements 72 and 94 cooperate to clamp and support the tubing during the bending or forming cycle and, due to the unique shape of the grooved portions therein, prevent collapse of or damage to the sidewalls of the tubing as it is bent.

It is to be observed that as ram 92 moves downwardly, the ram die 94 contacts tubing 27 and forces it against I the stationarily mounted wing die 59 so as to clamp it in afixed position.

At the position of the apparatus shown in FIG. 11, compression cylinders and 81 are filled with hydraulic fluid which is pressurized'so as to resist upward movement of pistons carried by piston rods 78 and 79. The amount of pressure resisting upward movement of piston rods 78 and 79 is regulated and balanced within cylinders 80 and 81 by a control valve mechanism 104 which includes a manifold. As is shown in FIG. 2, control valve 104 is operatively connected to cylinders 80 and 81 by conduits 105 and communicates with the remainder of the hydraulic system through conduit 106. It is noted that the conduits 105 are interconnected through the manifold of the valve mechanism 104 so that the hydraulic pressure in the cylinders 80 and 81 is at all times equal.

Referring now to FIG. 12, as ram 92 is caused to move downwardly, the ram die 94 contacts tubing 27 and the wing die 59. Continued downward movement by ram 92 causes a downward force to be exerted by ram 92 against stationary jaw means which, it is to be recalled, is rigidly fixed to supporting means 10. This downward force causes bending means 12 to smoothly pivot to the right about the axis of shaft 50 into the position shown in this view. In this position the ram die 94 can be seen to have rolled or pivoted relative to the stationary wing die 59. At the same time, forming means 70 carrying the wing die 72 has been caused to pivot or rotate about the axis of shaft 62. It is to be observed that piston rods 78 and 79 which are aflixed to ears 74 of sleeves 60 and 73 have, due to the pivotal movement of bending means 12 and forming means 70, telescoped into compression cylinders 80 and 81 against the pressure of the hydraulic fluid as regulated by control valve 104. It is this balanced force resisting the rotation of shaft 62 and the pivotal movement of bending means 12 which causes tubing 27 to be smoothly and uniformly bent. During the bending process as described, the unique design of the apparalows. To bend a length of tubing into a desired configuration, the tubing, identified by the numeral 27, is positioned in the apparatus with its left end supported by the wing die 59 of stationary jaw means 15 and its right end held captive by tube holding means 22. Circular protractor 28 is positioned at a starting reference or zero point, and tube holding means 22 is caused to move toward bending means 12 along supporting means 14 to a predetermined point, as indicated on tape measure 36. This positions tube 27 so that the centerline of the first bend which is to be made is aligned with the vertical centerline of second tube forming means 88. The depth or degree to which the tube is to be bent is controlled by bend control means 68, the details of which are illustrated in FIG. 2, and the operation of which will now be described. I

As can beseen in FIG. 2, selector means 68 has a tinger 110 which may be positioned relative to an index 112 which has graduations imprinted thereon. As the tube is bent, shaft 62 rotates in a counterclockwise direction, causing finger 110 to also rotate to apoint where it contacts a limit switch 114. Limit switch 114 is of a type well known in the hydraulics field and, in this sytem, is adapted to limit further flow of hydraulic fluid to the upper portion of ram cylinder 90, thereby stopping the downward movement of ram 92. To provide the correct depth of bend in the tube at this first location, the operator, prior to activating the hydraulic system, moves finger 110 into alignment with the indicia on index 112, indicating the degree of bend which the operator wishes to make.

Having now positioned the tubing longitudinally and rotationally relative to fixed reference points, and having appropriately set the depth of bend control means 68, the operator activates the hydraulic system. Ram 92 is caused to move downwardly to a point where the ram die 94 contacts tubing 27, clamping it against wing die 59 of stationary jaw means 15. Further movement of ram 92 causes bending means 12 to pivot about the axis of rotation of shaft 50 against the resistance of piston rod 79. As bending means 12 pivots, ram 92 continues to move downwardly and the ram die 94 rolls relative to stationary vise element 59. First tube forming means of bending means 12 is also caused to pivot about the axis of shaft 62 against the resistance piston rod 78. As ram 92 continues to move downwardly, the continued pivotal movement of the apparatus causes increased bending of the tubing. As the tubing bends, shaft 62 continues to rotate, causing finger 110 of bend control means 68 to also rotate to a position where it makes contact with limit switch 114. At this point, the flow of hydraulic fluid to the upper portion of ram cylinder 90 is stopped and hydraulic fluid is introduced at the lower portion of ram cylinder 90 through conduit 115, causing ram 92 to move upwardly. At the same time, the hydraulic pressure in compression cylinders and 81, as controlled by control valve 104, causes.

piston rods 78 and 79 to move downwardly. This downward movement, coupled with the relaxation of force by ram 92, forces a reversal of the pivoting action of I bending means 12 and first tube forming means 70, causing them to return once more to the starting position.

As can best be seen in FIG. 2, as bending means 12 rotates about the axis of rotation of shaft 50 "to the starting position shown, arm 58 contacts limit switch 116 of bending means 12, causing flow of fluid to ram cylinder to stop and the hydraulic system to come to equilibrium. The apparatus is now in a position to repeat the bending cycle and the operator may proceed with the second setup or tube positioning operation. In so doing, tube 27, without removing it from holding means 22, is caused to be moved by conveyor means 34 further to the left to a new centerline of bend, as selected on tape measure 36. Rotational positioning is accomplished by rotating the tubing through the desired angle, as determined by reference to index 28. The depth of bend desired at the second point along the tubing is achieved by the appropriate setting of bend control means 68, in a manner as previously described.

The setup having thus been completed, the hydraulic system may again be activated.

By repeating the, process as described, numerous bends of differing magnitudes lying in various planes at different locations along the tubing may be made.

It is to be appreciated that since one end of the tubing can be held fixed during the process as described multiple bends as desired may be made in the tubing, each being made in a known relationship with one another and with the original position of the tubing. This feature allows a high degree of accuracy and repeatability in the bending of tubing. As can also readily be appreciated, this feature allows automation of the setup process to a degree not possible with prior apparatus in which both ends of the tubing are, of necessity, free to move.

SECOND EMBODIMENT FIGS. 1332 show an improved embodiment of tube bending apparatus generally identified by the numeral Referring to FIGS. 13-15, the apparatus 200 has two frame sections 201 and 202 which are pivotally interconnected to be rotatable to a limited extent with respect to each other about a preferably vertically ex tending pivot axis. The pivot axis is defined by a vertically extending pipe 203 mounted on one end of the frame section 201. The pipe 203 provides a pivot mount for pivot pin 204. The pivot pin 204 is rigidly mounted centrally, as shown in FIG. 14, on the underside of the frame section 202 to extend vertically downward therefrom.

The frame section 201 has mounted on its end remote from the pipe 203 a pair of laterally spaced apart bender head mechanisms or means designated 205a and 20512 as are hereinafter described in more detail. The bender head mechanisms 205 extend in a substantially vertical plane and are mounted on frame members 206 which form part of the frame section 201. The frame section 201 is stably mounted on conventional rollers 207 and carries an hydraulic sump or reservoir 208 and a cabinet 209 which contains the systems electrical circuitry. A control panel 210 for controlling the operation of the apparatus 200 is mounted on the cabinet 209. v

The other frame section 202 is made up of a preferably horizontally extending longitudinal member 211 which is mounted on downwardly extending legs 212. The legs 212 are stably mounted on conventional rollers 213. The pivot pin 204 is secured in a central position on the longitudinal member 211 and the legs 212 are positioned on each side of the pivot 204 adjacent opposite ends of the longitudinal member 211.

The longitudinal frame member 211 is formed by a pair of parallel horizontally extending rails 215 interconnected by cross-supports 216. Mounted within the rails 215 and supported by the cross-supports 26 is a conventional conveyor chain mechanism 217 which is selectively driven by the conveyor motor 218. The motor 218 includes a torque reliever mechanism which may be set at any predetermined torque. The torque reliever mechanism permits the motor 218 to slip whenever the predetermined torque setting is exceeded.

Attached to the conveyor chain 219 of the conveyor mechanism 217 is a platform 220 which supports a selectively rotatable drum mechanism 221. The drum mechanism 221 is positioned with its axis of rotation extending parallel with the longitudinal axis of the longitudinal frame member 21 1, extending preferably horizontally. The drum mechanism 221 is described in more detail hereinafter and-is connected to be driven by a hydraulic motor 222. The output shaft of the drum 221 is connected to rotate a chuck mechanism 223. The chuck mechanism 223 is designed for gripping a length of tubing 224 to be bent. A set of auxiliary controls 225 is mounted on the housing of the motor 222 along with a conventional limit switch 235. The limit switch 235 has an actuatable contact in the form of a roller mechanism 236 which is actuated by selectively positionable stops 237 on one of the rails 215.

The apparatus200 is illustrated positioned on a substantially horizontal surface 240 with the frame section 202 aligned to feed tubing to be bent to the bender v head mechanism designated 205a. As shown in FIG; 13, lock mechanism 241 which may be of any suitable type is shown latching the frame sections 201 and 202 in this first position whereat the longitudinal axis of the frame 202 is aligned with the bender head. 205a.

The lock mechanism 241 illustrated is made up of over-lapping extensions 242 and 243. The extensions 242 and 243 are preferably flat and are mounted to extend horizontally towards each other from the frame member 206 and the adjacent leg structure 212, respectively. Aligned holes are formed in the extensions 242 and 243 through which a bolt mechanism 244 is secured to lock the frame sections 201 and 202 in place.

The frame section 202 is shown in dashed lines in FIG. 14 pivoted relative to the frame section 201 to a second position for feeding tubing to the bender head 205b. In this second position, the longitudinal axis of the frame 202 is aligned with the bender head 205b. Lock mechanism similar to the mechanism 241 is provided for locking the frame sections 201 and 202 in this second position. It is noted that the rollers 213 and 207 upon which the frame sections 202 and 201 are mounted, respectively, permit the frame sections to be readily pivoted with respect to each other between the first and second positions shown in FIG. 14.

FIGS. 16-19 illustrate in greater detail the tube feed mechanism made up of the drum mechanism 221, the

conveyor mechanism 217 and the chuck 223. As shown in FIG. 19, the rotatable drum 221 mounted on the platform 220 has its shaft 250 connected in driving relation with the hydraulic motor 222. The shaft 250 is conventionally mounted in bearings and a magnetic brake 251 is mounted within the drum 221 to control drum rotation.

The magnetic brake mechanism 251 includes a coil 252 which is operable when energized to pull the magnetic brake plate 253 against the coil face. The brake plate 253 operates to hold the drum 221 positively in position and the amount of friction provided by the brake plate 253 against the coil face is controlled by the setting of the adjustable mechanism 254. To rotate the drum 221, the hydraulic motor 222 is driven to overpower the braking force applied by the magnetic brake 251. Once the motor 222 stops driving, however, the magnetic brake 251 instantly locks the drum in the position to which it has been rotated by the motor 222.

As shown in FIG. 17, the outer peripheral surface of the drum 221 has a spiral groove 260 formed thereon. Stops 261, as shown in FIGS. 17 and 18, are mounted at selected positions in the groove 260 and a conventional limit switch 262 is mounted adjacent the drum 221 to ride in the groove 260. The limit switch 262 is slidably mounted on guide rods 263 so that it can move longitudinally relative to the drum 221 as the drum is rotated.

The positions of the stops 261 in the continuous spiral 260 determine the angular orientations of thebends made in the length of tubing 224. A protractor or angular scale 264 is mounted on the drum 221 to indicate its angular orientation and to aid in appropriately placing the stops 261 in the spiral groove 260.

As beforementioned, the drum 221 carries the limit switch 235 which is actuated by the stops 237 mounted on one of the longitudinal rails 215. As shown in FIG. 17, the limit switch 235 extends to the left side of the drum 221 to ride against the upper surface of the left rail 215. Thereby, as the drum 221 and platform 220 are advanced on rollers 270 longitudinally along the rails 215, the switch 235 is selectively actuated by the stops 237 to stop the axial advancement of the tube 224 at selected spaced apart points where a bend is desired.

Conventional limit switches 272 and 273 are also carried by the drum 221. As shown in FIG. 17, the limit switches 272 and 273 are mounted to extend to the right side. of the drum mechanism 221 to ride against the right rail 215. The switch 272 is designated the forward travel limit switch and is actuated by a stop not shown on the right rail 215 which is positioned at or near the forward end of the rail 215. Actuation of the switch 272 prevents the conveyor mechanism 217 from driving the drum 221 and platform 220 off the forward end of the rails 215.

The switch 273 is designated the rear travel limit switch and is actuated by the stop 274 shown in FIG. 17. The stop 274 is positioned at or near the rear end of the right rail 215. Actuation of the switch 273 stops the drum 221 in a start or index position on the rails 215.

The mechanism gripping the tube 224 is shown in greater detail in FIGS. 16 and 17. The chuck 223 has extensions 280 thereon which may be tightened to tightly hold the tube 224. The chuck 223 is connected by a double universal joint 281 to the shaft 250 of the drum 221. A preferably rectangular, upward opening guide 282 is mounted on the front of the drum 221 to restrict the movement of the double universal joint 281 to an upward vertical path. The purpose of the universal joint connection 281 is to permit the chuck 223 to flex the instant the tube 224 is axially advanced after a bend has been made therein. The fiexure of the chuck mechanism 223 in conjunction with the torque reliever mechanism of the conveyor motor 218 causes the tube 224 to be softly pushed through the bending head 205, thereby to aid the movement of the bent portion of the tube 224 out of the bending head 205. The torque reliever mechanism relieves the torque on the output shaft of the motor 218, for example, during the instant the tube 224 is still clamped by the bender head 205 after a bend has been completed when the motor 218 is started to advance the tube 224 to the next bend position. By limiting the movement of the joint 281 to an upward movement, changes in the angular orientation and longitudinal alignment of the tube 224 with respect to the bending head 205 are prevented. Mechanism, such as a spring mechanism, not shown in detail is included in the joint connection 281 for automatically returning the joint 281 from a flexed position to the straight ahead horizontal position shown in FIG. 17 once the bent portion of the tube 224 has cleared the bending head 205. g

One of the bender heads 205 is shown in detail in FIGS. 20-21. The bender head has a wing die 300 stationarily mounted on the fixed support means provided by the frame 206. The upwardly opening wing die 300 is mounted in longitudinal alignment with the axisof the tube 224 held in the chuck 223.

Pivotally mounted on a horizontally extending fixed shaft 301 is a ram mechanism or assembly 302 which includes an assembly frame carrying a ram cylinder 303 for reciprocating a ram die 304. The ram cylinder 303 has its piston connected to pull the arcuate ram die 304,

downwardly towards the tube 224 positioned in the wing die 300. The center line of the ram die 304 is aligned with the piston of cylinder 303. It is noted that the pivot axis defined by the shaft 301 and the path of movement of the ram die 304 are off centered on opposite sides of the center of the wing die 300. Thereby, the downward advancement of the ram die against the tube 224 held in the stationary wing die 300 causes the ram mechanism to rotate about the axis 301.

Mounted on rotatable shaft 305 on the frame of the ram mechanism 302 is a pivotable wing die 306. As

It is noted that the dies 300, 304 and 306 are all positioned to lie in the same vertically extending plane. It is also noted that the dies are removable and are shown mounted on spacer plates or shims 307 which function to correctly space the dies with respect to each other. Thereby die sets designed for different diameter tubing and for making bends of different radius may be readily incorporated into the bender head mechanism 205.

In order to clamp the tube 224 during a bend, hy-

' draulic cylinders 310 and 311 are provided. As shown in FIGS. 22 and 23, the cylinder 310 is physically connected between a; rigid extension 312 from the fixed shaft 301 and a point on the lower frame portion of the ram mechanism 302. The extension 312 is held in a stationary position by splines 313 on the shaft 301. The compression cylinder 310 monitors the clampingpressure between the ram die 304 and the stationary wing die 300 and resists rotation between the frame of the ram mechanism assembly 302 and the fixed support means provided by the frame 206.

The compression cylinder 311 .is connected between a lower point on the frame portion of the ram mechanism 302 and an extension 314 from the rotatable shaft 305. Splines 315 hold the extension 314 in a fixed position on the rotatable shaft 305. The cylinder 31] monitors the clamping pressure between the ram die 304 and the wing die 306 since it is compressed by the rota- 7 tion of the ram mechanism 302 away from the upright stationary frame member 206, as shown in FIG. 23. The compression cylinder 311 operates to resist rotation between the wing die 306 and the frame of the ram mechanism assembly 302.

FIG. 24 illustrates the portion of hydraulic circuit 320 of the apparatus 200 which is associated with the ram cylinder 303 and the resistance or compression cylinders 310 and 311.

The hydraulic circuit 320 includes asolenoid operated spool valve 321 which has a pressure port P, a tank draulic line 325 in communication with the rod end of the ram cylinder 303. The B port of valve 321 is connected through hydraulic lines 326 and 327, respectively, to the piston end of ram cylinder 303 and to the manifold 328. The manifold 328 is shown physically in FIG. 13 and has a pressure gauge 329 connected in communication with its manifold chamber 330.

As shown by directional arrows in FIG. 24, hydraulic fluid may flow from the line 327 into the manifold chamber 330 through spring-loaded check valve 331 or out of the chamber 330 to the line 327 through springloaded checkvalve 332. The manifold chamber 330 is connected in communication with the piston sides of the hydraulic compression cylinders 310 and 311 through hydraulic lines 333 and 334.

In operation of the hydraulic circuitry 320, the cylinders 303, 310 and 311 are extended by the hydraulic fluid received through line 322 whenever the solenoid valve 321 is in its straight position. With the hydraulic cylinders 303, 310 and 311 extended, the bender head mechanism is positioned upright as shown in FIGS. and 22.

Whenever the solenoid valve 321 is switched to its crossover position, the pressurized hydraulic fluid from line 322 is directed to the A port and the hydraulic lines 326 and 327 are connected to tank through valve ports B and T. Direction of pressurized fluid out port A of the valve 321 retracts the ram cylinder 303 to cause a bending operation as shown in FIGS. 21 and 23.

Once the ram die 304 is advanced by retraction of the cylinder 303 to contact a tube 224 positioned in the wing dies 300 and 306, further retraction of the cylinder 303 tends to rotate the frame of the ram mechanism 302. This rotation of the ram mechanism frame is resisted by the hydraulic fluid in the extended compression cylinder 310. As the ram cylinder 303 continues to be retracted a clamping pressure measured by the pressurein the cylinder 310 is builtup between the dies 304 and 300 until the fluid in the cylinder 310 reaches a pressure equal to the setting of the check valve 332. The check valve 332 then opens to dump excess fluid in the cylinder 310 to tank and the frame of the ram mechanism 302 rotates about the fixed shaft 301.

As. the frame of the ram mechanism 302 rotates, pressure is built up in the compression cylinder 311 to develop a clamping pressure between the dies 304 and 306. The pressure builds up until a clamping pressure equal to the setting of check valve 332 is reached in the cylinder 311. The check valve then dumps excess fluid in the cylinder 311 to tank and the wing die 306 rotates, as shown in FIG.' 21, against the ram die 3.04 to bend the tube'224 while holding it clamped therebetween at a controlled clamping pressure. 7

It is noted that by connecting the piston ends of the compression cylinders 310 and 3.11 in communication with each other through the manifold chamber 330 that equal clamping pressures will be applied to the tube 224 by both the dies 304, 300 and the dies 304, 306. Thus, the dies 300, 304 and 306 move during a bending operation in a smooth regular manner with respect to each other to stretch the tube 224 around the ram die 304. The clamping pressure of the dies 300, 304 and 306 on the tube 224 may be controlled by adjusting the setting of the adjustable check valve 332 and the gauge 329 will indicate this balanced clamping pressure during a bending operation.

FIGS. 25-31 illustrate the depth of bend gauge mechanism 340 associated with each bender head mechanism 205. The depth or degree of bend made in a tube The depth of bend mechanism 340 uses the angular measure provided by the rotation of the shaft 305 to control the distance of retraction of the ram cylinder 303. Thereby, the degree of bend made in the tube 224 is controlled in the programmed manner hereinafter described. I

The depth of bend gauge mechanism 340 includes a wheel 341 having an annular peripheral surface for carrying a programming tape 342. The tape 342 is preferably made of a flat strip of flexible metal. The tape 342 is punched with a series of angularly spaced apart holes 364 in a selected manner to program the depth to which the ram cylinder 303 is retracted during the sequential bending operations associated with bending a length of tubing 224 into a desired shape. Thereby, the depth of each of the bends in a tube 224 is controlled as a function of the angular spacing between adjacent holes 364 punched in the tape 342.

The depth of bend gauge mechanism includes a conventional rachet mechanism 343. The rachet 343 is connected to bedriven by the rotatable shaft 305 to which the pivotal wing die 306 is affixed. The rachet 343 has one shaft portion 344 which is connected to the shaft 305 to be rotatable in either a clockwise or counterclockwisesense therewith. Positioned around the shaft portion 344 is a pointer 345 which may be clamped thereto by tightening a thumb screw 346.

The rachet 343 has another shaft portion 347 which is only rotatable in one sense, the sense being the direction in" which the shaft 347 is driven by rotation of the shaft 305 during the bending of a tube by the die 306. The wheel 341 is mounted on the shaft portion 347 by a bolt 348. Tightening of the bolt 348 secures the wheel 341 tightly to the rachet shaft 347 for rotation there'- with. It is noted, as shown in FIG. 28, that the wheel 341 is rotated counterclockwise by the rachet shaft 347 302 is a protractor 350, preferablydefining an arc of The protractor 350 is for use with the pointer 345. A punch mechanism 351 for punching holes in the tape 342 is also mounted on the frame of the ram mechanism 302 in a selected position relative to the wheel 341, preferably just below the wheel 341.

A tape 342 for programming the depths of a series of bends may be made in the following manner. The bolt 348 and thumb screw 346 are loosened so that the wheel 341 and pointer 345 are free to rotate relative to rachet mechanism 343. The wheel 341 is then rotated to alignits ZERO reference mark with the 0 degree mark on the protractor 350. A first hole is punched in an end of the tape 342. This'tape end is secured to the wheel 341 in a diametrically opposite position to the ZERO reference mark by hooking the pin 352 on the periphery of the wheel 341 through the first tape hole. A hole 364 indicating program start position is now punched in the tape 342. The pointer is then rotated clockwise to a selected reading on the protractor 350. For example, rotation of the pointer 350 to a reading of 45 is equivalent to setting a depth of bend of 90. The wheel 341 is now rotated counterclockwise to position the pointer on the 0 degree mark of the protractor 350, as shown in FIG. 26. Another hole 364 is now punched in the tape 342 by the punch mechanism 351.

The pointer 345 is repositioned and the above procedure is repeated to program a predetermined sequence of depth of bends on the tape 342.

Once the selected number of holes desired have been punched in selected locations in the tape 342, the tape 342 is cut at an appropriate length and a hole is punched in the tape adjacent its cut end. The cut end of the tape 342 is then secured to the periphery of the wheel 241, as shown in FIG. 31, by passing the pin 353 on the rod mechanism 355 mounted in the wheel.341 through this end hole. The wheel 354 is then turned to retract the threaded rod 355 carrying the pin 353, thereby to tightly stretch the tape 342 around the annular periphery of the wheel 34]. I

It is noted that the angular spacing between the reference marks END and ZERO in a clockwise sense represents the usable part of the tape 342 resulting from the angular spacing between the position of the pin 352 when the wheel 341 is at ZERO reference position and the location of the punch 351.

Mounted on the frame of the ram mechanism 302 in a selected position relative to the periphery of the wheel 341 is a switch arm 360 carrying a pin 361 on one end. The arm 360 is pivotally mounted on pivot pin.

362. A tension spring 363 is connected between the frame of the ram mechanism 302 and the end of the arm 360 remote from the pin 361. The spring 363 operates to pivot the arm 360 towards the wheel 341 so that the pin 361 rides in contact with the tape 342. The pin 361 is dimensioned to fit within the hole 364 punched in the tape 342, as shown in FIG. 30, and is held in a suitable position against the tape 342 to fallwithin a hole 364 as a'hole 364 in the tape is moved past by rotation of the wheel 341. Thereby, tape holes 364 are sensed. I

Positioned adjacent the end of the arm360 to which the spring 363 is connected is a selectively actuatable solenoid 365 which when energized overcomes the force of the spring 363 and pivots the arm 360 to lift the pin 361 out of a tape hole 364. Connected to the end of the arm 360 carrying the pin 361 is the movable contact 366 ofa two position limit switch 367. The limit switch 367 operates to indicate whether or not the pin 361 is inserted within a tape hole 364, and to generate control signals as a function of the angular spacing between adjacent tape holes 364.

In operation of the depth of bend gauge mechanism 340, at tape 342 punched in a selected manner is secured around the annular periphery of the wheel 34] and the wheel 341 is clamped in a selected start position. The solenoid 365 is actuated at the start of a bend cycle to pivot the pin 36] of the arm 360 out of a hole in the tape 342. The ram cylinder 303 is, then actuated and a tube 224 is bent. As the tube 224 is bent the wing die 306 rotates the shaft 305, thereby rotating the wheel 341 counterclockwise, as shown in FIG. 28. During the bending of a tube 224, the pin 361 rides along the surface of the tape 342 as the wheel 341 is rotated. It is noted that the solenoid 365 is not energized during the actual bending operation so that once the wheel 341 rotates a tape hole 364 into alignment with the pin 361, the pin 361 will fall therein due to the tension spring 363. The dropping of the pin 361 into a tape hole 364 actuates the limit switch 367 to stop the retraction of the ram cylinder 303. Thereby, the degree or depth of bend of the tube 224 is controlled as a func tion of the angular spacing between adjacent tape holes 364.

The ram cylinder 303 is then returned to its extended position to rotate the frame of the ram mechanism 302 about the stationary shaft 301 back to its upright position. Return of the ram mechanism 302 to its upright position causes the lever 370 on the fixed shaft 301 to actuate a movable contact 371 on a limit switch 372 which is carried by the frame of the ram mechanism 302. Actuation of the limit switch 372 indicates the end of a bend cycle.

FIGS. 28 and-25 illustrate the actuation of the limit switch 372 by the'lever 370 on the shaft 301. FIG. 28 shows the lever 370 positioned relative to the switch 372 when the frame of the ram mechanism 302is in a position rotated away fromits upright position. FIG. 25 shows actuation of the switch contact 371 by the lever 370 when the ram mechanism 302 is positioned upright, i

Referring now to FIG. 32, a diagram of the electrical circuitry which programs and generates control signals to control the operation of the apparatus 200 is there shown. 220 volt, three phase, 60 herz A.C. is supplied to electrical lines 380 through ashort circuit protection mechanism 379. The lines 380 are connected through motor starter contacts 381 and overload fuse mechanism 382 to a three phase hydraulic pump motor 378 which supplies pressurized fluid to the hydraulic system of the apparatus 200. The lines 380 are also connected to the primary winding of transformer 383.

The secondary winding of the transformer 383 is connected through a resetable fuse 384 to supply volt,

6O herz A.C. across the voltage buses or lines 385-386 and 510-386. The line 386 is grounded. To energize the hydraulic pump motor 378, switch 387 is momentarily closed. Electrical current then flows through normally closed switches 388 and 389, and switch 387 to energize motor starter coil 3,90. Energization of coil 390 closes motor starter contacts 381 and contact 391 across the switch 387. Thereby, the hydraulic pump motor 378 is energized until one of the switches 388 or 389 is selectively opened or the overload fuse mechanism 382 causes the normally closed contact 392to open.

Energization of the motor starter coil 390 also closes contacts 393 to supply the voltage on line-385 to line 394. r

A two position manual switch 395 has its movable contact connected to line 394. Positioning of .the switch 395 in its H or hand position connects'the line 394 to electrical line 396. i

With switch 395 on the H contact, the apparatus 200 may be operated in the following manner. Connection of the movable contact of the switch 400 with line 396 energizes the magnetic brake mechanism 251 associated with the drum 221 and hydraulic motor 222. Closure of switch 401 sequentially steps a stepping switch 402 having sequentially positioned contacts 403, 404 and 405. The contacts 403 are associated 'with the conveyor motor 218 which advances a length of tubing towards a bending head 205. The contacts 404 are associated with the hydraulic motor 222 which rotates thedrum 221. The contacts 405 are associated with the ram cylinder 303 which is retracted to make a bend.

Depression of switch 410 energizes forward solenoid 411. Energization of solenoid 411 drives the conveyor 

1. Apparatus for bending tubing, tubular stock and the like, comprising: fixed support means; ram assembly means including a frame, a hydraulic ram cylinder and an arcuate ram die. said ram cylinder being mounted in a selected position on said assembly frame and having its piston connected to said ram die with the center line of said ram die aligned with the piston of said ram cylinder whereby selective extension or retraction of the piston of said ram cylinder moves said ram die along a predetermined path of travel; means pivotally mounting said assembly frame on said fixed support means for rotation about a horizontal axis; a first hydraulic compression cylinder connected to resist rotation between said assembly frame and said fixed support means, said first compression cylinder being operable in its extended position to hold said ram cylinder upright with said ram die facing vertically downward; first and second wing dies designed for receiving and holding a tubular member to be bent; means stationarily mounting said first wing die horizontally on said fixed support means in said predetermined path of travel of said ram die a given distance to one side of the center line of said ram die to face vertically upward in alignment with said ram die; means pivotally mounting said second wing die on said assembly frame in said predetermined path of travel of said ram die a given distance to the other side of the center line of said ram die for rotation in the vertical plane of alignment Of said ram and first wing dies away from a horizontally aligned side by side position with said first wing die; a second hydraulic compression cylinder connected to resist rotation between said assembly frame and said second wing die, said second compression cylinder being operable in its extended position to hold said second wing die in a side by side position relative to said first wing die; hydraulic means connected to said first and second compression cylinders for selectively supplying pressurized hydraulic fluid thereto to extend said compression cylinders; manifold means connected to said first and second compression cylinders for controlling the flow of hydraulic fluid therefrom once said compression cylinders are extended to maintain equal pressures in said compression cylinders not greater than a predetermined pressure level; and means for selectively actuating said hydraulic ram cylinder to advance said ram die into engagement with said wing dies whereby to effect a bend of a tubular member held thereby.
 2. The invention defined in claim 1, including depth of bend control means for selectively controlling the distance said ram die is advanced by said ram cylinder along said path of travel during a bending operation.
 3. The invention defined in claim 2, wherein said depth of bend control means includes: a wheel having an annular rim portion; a program tape secured around said wheel rim portion, said tape having holes punched at selected locations therein; rachet means connecting said wheel with said second wing die for rotation of said wheel with said second wing die only in the direction said second wing die rotates during the bending of a tubular member; means for sensing the rotation of holes in said tape to a reference point and generating control signals as a function of the angular spacing between adjacent holes in said tape; and means responsive to said control signals for selectively controlling the distance said ram die is advanced by said ram cylinder.
 4. The invention defined in claim 3, wherein said means for sensing holes and generating control signals is a limit switch having pin means positioned to drop into a hole in said tape when the hole is rotated to said reference point.
 5. The invention defined in claim 1, including: means for horizontally holding a tubular member to be bent in alignment with said first wing die; means for selectively advancing tubular member held by said holding means past said first wing die to selected longitudinal positions between said ram die and said wing dies; means for selectively rotating said tubular member held by said holding means to selected orientations; and means for programming the operation of said advancing means, said rotating means and said means for actuating said hydraulic ram cylinder whereby a plurality of bends may be made in a tubular member at selected longitudinal positions and selected orientations.
 6. Apparatus for bending tubing, tubular stock and the like, comprising: fixed support means; ram assembly means including a frame, a hydraulic ram cylinder and an arcuate ram die, said ram cylinder being mounted in a selected position on said assembly frame ahd having its piston connected to said ram die with the center line of said ram die aligned with the piston of said ram cylinder whereby selective extension or retraction of the piston of said ram cylinder moves said ram die along a predetermined path of travel; means pivotally mounting said assembly frame on said fixed support means for rotation about a horizontal axis; a first hydraulic compression cylinder connected to resist rotation between said assembly frame and said fixed support means, said first compression cylinder being operable in its extended position to hold said ram cylinder upright with said ram die facing vertically downward; first and second wing dies designed for receiving and holding a tubular member to be bent; means stationarily mounting said first wing die horizontally on said fixed support means in said predetermined path of travel of said ram die a given distance to one side of the center line of said ram die to face vertically upward in alignment with said ram die; means pivotally mounting said second wing die on said assembly frame in said predetermined path of travel of said ram die a given distance to the other side of the center line of said ram die for rotation in the vertical plane of alignment of said ram and first wing dies away from a horizontally aligned side by side position with said first wing die; a second hydraulic compression cylinder connected to resist rotation between said assembly frame and said second wing die, said second compression cylinder being operable in its extended position to hold said second wing die in a side by side position relative to said wing die; hydraulic means connected to said first and second compression cylinders for selectively supplying pressurized hydraulic fluid thereto to extend said compression cylinders; manifold means connected to said first and second compression cylinders for controlling the flow of hydraulic fluid therefrom once said compression cylinders are extended to maintain equal pressures in said compression cylinders not greater than a predetermined pressure level; means for selectively actuating said hydraulic ram cylinder to advance said ram die into engagement with said wing dies whereby to effect a bend of a tubular member held thereby; means for horizontally holding a tubular member to bend in alignment with said first wing die and for selectively rotating said tubular member held by said holding means to selected orientations, said holding and rotating means including: a rotatable drum, brake means for braking the rotation of said drum, a motor connected to drive said drum, and a chuck for gripping an end of the tubular member to be bent, said chuck being positioned to hold a tubular member horizontally and being connected with said drum to rotate therewith, said drum being held in place by said brake means until said motor is selectively energized to overcome the braking force of said brake means; means for selectively advancing a tubular member held by said holding means past said first wing die to selected longitudinal positions between said ram die and said wing dies, said advancing means being a conveyor means; and means for programming the operation of said advancing means, said rotating means and said means for actuating said hydraulic ram cylinder whereby a plurality of bends may be made in a tubular member at selected longitudinal positions and selected orientations.
 7. The invention defined in claim 6 wherein said programming means includes means for generating signals to control the energization of said motor driving said drum which comprises: a spiral groove formed around the periphery of said drum; stops selectively positioned in said groove; and a limit switch means for generating said signals positioned to ride in said groove, said limit switch means being selectively actuated by said stops.
 8. The invention defined in claim 7, including: double universal joint means connecting said chuck to said drum to permit flexure therebetween; guide means positioned around said universal joint to limit the direction of any flexure of said universal joint to a vertically upward movement; and means resiliently biasing said universal joint in a horizontal position; and wherein: said conveyor means includes a conveyor motor having mechanism which relieves torque on its output shaft to compensate for momentary forces opposing advancement of the conveyor means.
 9. The invention defined in claim 8, including depth of bend control means for selectively controlling the distance said ram die is advanced by said ram cylinder along said path of travel during each bending operation.
 10. The invention defined in claim 9, whErein said dies are removable and include spacer plates dimensioned to correctly position said dies relative to each other when mounted in said bending apparatus.
 11. The invention defined in claim 1, including: a second bending apparatus as defined in claim 1 designed to bend tubular members to form mirror images of tubular members bent by the bending apparatus defined in claim 1, said second bending apparatus being positioned laterally spaced apart from the bending apparatus defined in claim 1; and means selectively positionable to feed tubular members to be bent to either said second bending apparatus or the bending apparatus defined in claim
 1. 12. Apparatus for bending tubing, tubular stock and the like, comprising: fixed support means; a stationary wing die mounted on said support means adapted to seat a member to be bent; an assembly pivotally mounted on said support means including a rotatable wing die and a linearly reciprocalble ram die opposing said wing dies, said dies being aligned in a vertical plane and said rotatable wing die being pivotally mounted for limited rotation away from said stationary wing die in said vertical plane; hydraulic means for advancing said ram die into engagement with the member to be bent and said stationary wing die whereby the member to be bent is held and said assembly and rotatable wing die are rotated; a first hydraulic compression cylinder means physically connected to resist rotation between said assembly and said support means; a second hydraulic compression cylinder means physically connected to resist rotation between said rotatable wing die and said assembly; and manifold means connected to said first and second compression cylinder means for controlling the flow of hydraulic fluid therefrom to maintain equal pressures in said compression cylinder means not greater than a predetermined pressure level.
 13. In a tube bending apparatus having a fixed wing die and a pivotable wing die aligned in a selected plane to hold a tubular member to be bent and in which a ram die is selectively advanced into engagement with said wing dies in said selected plane of alignment to effect a bend of a tubular member held thereby, the improvement in combination therewith of: means for holding a tubular member to bend in alignment with said fixed wing die and for selectively rotating said tubular member held by said holding means to selected orientations, said holding and rotating means including: a rotatable drum, brake means for braking the rotation of said drum, a motor connected to drive said drum, a chuck for gripping an end of the tubular member to be bent, said chuck being positioned to hold a tubular member in alignment with said fixed wing die and being connected with said drum to rotate therewith, said drum being held in place by said brake means until said motor is selectively energized to overcome the braking force of said brake means; means for selectively advancing a tubular member held by said holding means past said fixed wing die to selected longitudinal positions between said ram die and said wing dies; and means for programming the operation of said advancing means, said rotating means and the selective advancement of said ram die whereby a plurality of bends may be made in a tubular member at selected longitudinal positions and selected orientations.
 14. The invention defined in claim 13, wherein said programming means includes means for generating signals to control the energization of said motor driving said drum which comprises: a spiral groove formed around the periphery of said drum; stops selectively positioned in said groove; and a limit switch means for generating said signals positioned to ride in said groove, said limit switch means being selectively actuated by said stops.
 15. The invention defined in claim 13, including: double universal joint means connecting said chuck to said drum to permit flexure therebetween; gUide means positioned around said universal joint to limit the direction of any flexure of said universal joint to movement in said selected plane of alignment of said dies; and means resiliently biasing said universal joint in a selected position in longitudinal alignment with said fixed wing die.
 16. The invention defined in claim 14, including depth of bend control means for selectively controlling the distance said ram die is advanced during each bending operation.
 17. The invention defined in claim 13, wherein said dies are removable and include spacer plates dimensioned to correctly position said dies relative to each other when mounted in said bending apparatus.
 18. The invention defined in claim 16, wherein said depth of bend control means includes: a wheel having an annular rim portion; a program tape secured around said wheel rim portion, said tape having holes punched at selected locations therein; rachet means connecting said wheel with said pivotable wing die for rotation of said wheel with said pivotable wing die only in the direction said pivotable wing die rotates during the bending of tubular member; means for sensing the rotation of halves in said tape to a reference point and generating control signal as a function of the angular spacing between adjacent holes in said tape; and means responsive to said control signals for selectively controlling the distance said ram die is advanced.
 19. The invention defined in claim 18, wherein said means for sensing holes and generating control signals is a limit switch having pin means positioned to drop into a hole in said tape when the hole is rotated to said reference point.
 20. The invention defined in claim 14, including depth of bend control means for selectively controlling the distance said ram die is advanced during a bending operation.
 21. The invention defined in claim 20, wherein said depth of bend control means includes: a wheel having an annular rim portion; a program tape secured around said wheel rim portion, said tape having holes punched at selected locations therein; rachet means connecting said wheel with said pivotable wing die for rotation of said wheel with said pivotable wing die only in the direction said pivotable wing die rotates during the bending of a tubular member; means for sensing the rotation of holes in said tape to a reference point and generating control signals as a function of the angular spacing between adjacent holes in said tape; and means responsive to said control signals for selectively controlling the distance said ram die is advanced.
 22. The invention defined in claim 21, wherein said means for sensing holes and generating control signals is a limit switch having pin means positioned to drop into a hole in said tape when the hole is rotated to said reference point.
 23. In a tube bending apparatus wherein a ram die is selectively advanced into engagmeent with a pair of aligned wing dies at least one of which is pivotable to effect a bend of a tubular member held thereby, the improvement of depth of bend control means for selectively controlling the distance said ram die is advanced during a bending operation, said depth of bend means comprising: a wheel having an annular rim portion; a program tape secured around said wheel rim portion, said tape having holes punched at selected locations therein; rachet means connecting said wheel with the pivotable one of said wing dies for rotation of said wheel with said pivotable wing die only in the direction said pivotable wing die rotates during the bending of a tubular memer; means for sensing the rotation of holes in said tape to a reference point and generating control signals as a function of the angular spacing between adjacent holes in said tape; and means responsive to said control signals for selectively controlling the distance said ram die is advanced.
 24. The invention defined in claim 23, wherein said means For sensing holes and generating control signals is a limit switch having pin means positioned to drop into a hole in said tape when the hole is rotated to said reference point. 